Up to 100,000 Ryanair passengers face disruption as the budget airline grounds 600 European flights next week due to cabin crew strikes.

The carrier, which is one of Europe's largest airlines, made the dramatic announcement that it will cancel 12% of its daily flights across the continent.

A total of 300 of its 2,400 scheduled flights will not take off each day next Wednesday and Thursday, as cabin crew mount pickets in Spain, Portugal and Belgium.

Some 12% of the airline's customers will be affected by the 48-hour industrial action by the crew who want "fair" pay and better terms and conditions.

The news comes as up to 8,000 passengers from Ireland will already be hit this week and next, as the airline's Dublin-based pilots are set to mount another two stoppages.

In addition, it was announced last night that a number of flights to and from Spain, Portugal and Belgium will be cancelled due to the strikes by cabin crew on two days next week.

The airline is cancelling 24% of its flights to and from Spain, 27% of flights to and from Portugal and 31% of flights to and from Belgium on the two days.

It is not known if flights to and from these popular holiday destinations to Irish airports will be affected.

A Ryanair spokesperson did not respond to a request for clarification on this matter last night. But the airline said it was contacting affected passengers, and it was seeking to minimise disruption to its customers from the "unnecessary" strikes.

Ryanair's chief marketing officer Kenny Jacobs apologised to customers. "Given that Ryanair cabin crew enjoy great pay - up to €40,000 per annum (in countries with high youth unemployment) - industry leading rosters (14 days off each month), great sales commissions, uniform allowances and sick pay, these strikes are entirely unjustified," he said.

He said the industrial action will achieve nothing other than to disrupt family holidays and benefit competitors in Belgium, Portugal and Spain.

The airline is suffering a turbulent period as pilots mounted their first strike in the history of the airline last week. They are planning a second stoppage tomorrow and another next Tuesday and their union is not ruling out ramping up the industrial action.

A total of 24 flights between the Republic and the UK have been cancelled tomorrow, and a similar number are likely to be affected during the third strike next week. Talks between both sides took place yesterday - but there was no breakthrough.

Fórsa spokesperson Niall Shanahan said the discussions - attended by the General Secretary of the Irish Congress of Trade Unions, Patricia King - were "useful" and the union would seek another meeting.

When asked about further disruption, he said: "I don't want to predict beyond the notice that's already been announced."

As it stands, tomorrow's strike is likely to go ahead, and there is another scheduled to take place next Tuesday. There was "no material change" to the situation, he said, and still "some considerable distance" between the parties.

Pilots want a 'seniority' system to be rolled out, to give those with the longest service first call on holidays, promotions and transfers.